Turbine blade and vane.



No. 856,630. PATENTED JUNE 11, 1907. J. s. GREEN.

TURBINE BLADE AND VANE. APPLIOATION FILED JAN. 2. 1907.

I VITNESSES: INVENTOR. 2

UNITED STATES PATENT OFFICE JONATHAN S. GREEN, OF PITTSBURG, PENNSYLVANIA, ASSIGNOR TO THE WESTINGHOUSE MAOHIN E COMPANY, A CORPORATION OF PENNSYLVANIA.

Specification of Letters Patent.

Patented June 11, 1907.

Application filed January 2,1907. Serial No. 350,417.

To all whom it may concern:

Be it known that I, JONATHAN S. GREEN, a citizen of the United States, and a resident of Pittsburg, in the county of Allegheny and State of Pennsylvania, have made a new and useful invention in Turbine Blades and Vanes, of which the following is a specification. I

This invention relates to blades for elastic fluid turbines.

In the manufacture of elastic fluid turbines, various metals have been used for the blades and vanes thereof, such as copper, bronze, nickel, nickel alloys, iron and steel. It has also been proposed to: galvanize, sherardi ze, plate or enamel blades for the purpose of obtaining a satisfactory core portion and a satisfactory cover or envelop.

Blades produced from any of the single or allo ed metals heretofore used, or protected bla es produced by any of the methods heretofore used, so far as I am aware, have proven unsatisfactory in use for various reasons. The rotors and stators of elastic fluid turbines, especially those of any size, are made of steel or iron, and with thetempcrature changes encountered as well as the centrifugal forces, in producing a satisfactory turbine blade or vane we are confronted with other roblems aside from the deterioration of the blade or vane from erosion and corro sion. It has been found that steel blades, while satisfactory in many respects, cannot be used on account of their deterioration and vanes from both erosion and corrosion: co per,-

cover and the blade proper, and further, be-

cause of the liability of the cover to chip or crack off from other causes encountered in the operation of turbines.

An object of this invention has, therefore, been to produce a turbine blade or vane, the

core or ma or portion of which will have the same co-e cient of expansion as the blade or vane holding element, and which is provided with a rotective covering of such metal as will wit stand the erosive and corrosive action encountered, and produced in such a manner that the cover or armor cannot crack or chip off.

A further object has been to produce a turbine blade or vane, the core or major portion of which is formed from metal having the same coefficient of expansion as the blade or vane holding element, with a protective armor or sheath welded to the core or major portion.

In the drawings accom anying this applica tion and forming a part t ereof: Figure 1 is a perspective view of a fragmentary portion of a blade or vane holding element of a turbine showing a ortion of a row of blades or vanes mounted t 'ierein; Fig. 2 is an end view of two of the blades or vanes of a turbine showing suitable means for lashing their outer or free ends together.

Each blade or vane preferably comprises adrawn steel core 3, which is provided with a sheath or cover 4 welded thereto and preferably formed of copper. The rotor element of the turbine is provided with slots 5 in which the blades are mounted. Any suitable method of mounting the blades may be employed, but in the method illustrated in the drawings the blades are inserted in the slot 5 and secured in place by means of calking pieces 7, which are inserted in the slot between the blados and are transversely expanded by ressurc, so as to grip the walls of the slot ant the faces of the end portions of the adjacent blades. The calking ieces 7 are made of the same material as t e rotor element and the cores of the blades so that the several elements of the organized structure will contract and expand, due to temperature variations, in the same degree. Such a condition is essential, in order that the bladeswill remain tight in the slot. The vanes are mounted in the same manner in slots 5 which are formed in the stator. The outer or free ends of the blades or vanes, in each row, are connected together in sets b means of a suitable binding wire 8, which is inserted through holes punched .near the outer ends of the blades or vanes.

I have shown the same form of binding wire as disclosed in United States Letters Patent No. 7 91,837 issued to Charles E. l is no tendency to chip, crack or peel off when Sweet on June 6, 1905, but instead of making the wire, as shown in said patent, of one metal, I referably'make mine of two metals, that is, fprov ide a steel or iron core for the body portion of the wire and a protective covering, pi'eferably-ofeopper, for thefin portion, which covering extends to formthe fin 11, which is sheared off between adjacent IO blades or vanes to form spacers as described in said patent.

y In mamifacturing the blades or vanes which comprise my invention, an ingot or billet of mild steel or iron is provided with a r 5 protective metal cover or envelop, which is welded onto it by a process which has proven to be effective. The billet with its. protective covering is worked as an integral mass and is eventually drawn or rolled into strips of the desired blade section and cut into proper blade lengths. When the blades are formed in this manner the ends of the cores are unprotected, but it has been found by experiment that the erosive, and corrosive action of the Steam and water does not affect the core. at the end of the blade when the ends only are exposed;

During the operation of drawing the blades ,the'protective metal utilized is worked and 0 compressed between the hard steel die and the hard blade core until it becomes homogeneous. When single 01-. alloy metal blades or'vanes having a different co-efiicientof expansion from the blade or vane holding ele- 3 5 ments are used, several difficulties arise. If the co-efiicient of expansion of the metal from which the blade is made is less than that.

of the holding element; under the high temperatures encountered in operating the turbine, the blades will loosen and become dis- 10d ed by the centrifugal, force encountered. If t e co-efficien't of expansion of the blade metal is greater than that of the holding element, under the temperatures encountered in operation, those portions of the blades lying below the surface of the mounting element become crushed or com ressed beyond the elastic limit of the meta and with a decrease in tem erature the blades become loose. With bla es manufactured in accordance with this invention, however, having a steel or iron core of the same co-efiicient of expansion as the mounting element, if the mounting element is made of steel or iron, the protective 5 5 cover, owin to its thinness, does not cause any harmfuI result, for the core or major portion of the blade will expand and contract under varying tem eratures as though no cover were present. he welding process holds the cover securely in place on the core and there subjected to the varying strains occasibned by the temperatures encountered. The

binding wire 8 is formed in substantially the same'manner, the dies for forming it being of difi'erent cross section and provided with the ncegsaryslot for forming the projecting fin.

.Various and other methods may be employed in the manufacture; for example, afa ter the billets are worked down to the proper size the blades may be formed by drop forging or stamping and various thicknesses of protective metal may be employed. Each blade may be provided with a protective covering which is separately welded thereto, al- .75 though this would be a tedious and expensive operation.

Having thus described my invention, what I claim as'new and useful and desire tosecure by Letters Patent is:

1. In combination with a turbine blade holding element, a turbine blade, thecore or major portion of which is formed of metal having substantially the-same coefiicient of expansion as the metal of said element and a 8 5 relatively thin sheath or cover welded to said core and formed of metal adapted to Withstand the erosive and corrosive effect of the Working fluid. v

2. In combination with a-turbine blade 0 holding element, a turbine blade, the core or major portion of which is formed of a metal having substantially the same coefiicient of expansion as the metal -ofsaid element and a relatively' thin sheath or cover of protective metal welded thereto'. I

3. In combination with aturbine blade holding element, a turbine blade, the core or major portion of which is formed of a metal having substantially the same coefficient of I00 expansion as the metal of said element and.

a relatively thin sheathof copper welded thereto.

4. In combination with a' steel or iron blade holding element, a turbine blade comprising a core portion formed of steel or iron and a relatively thin sheath or cover of cop per welded thereto.

5. In combination with a steel or iron blade holding element, a turbine blade com- 1 1o JNO. S. GREEN. 7 l/Vitnesses:

CHARLES W. MCGHEE,

E. W. MoCALLIsrER. 

